1. Field of the Invention
The present invention generally relates to methods and apparatus for collecting an aqueous sample for use in making a qualitative analysis of the sample to determine the condition thereof. More particularly, the invention relates to methods and apparatus for automatically and continuously collecting samples from any one of a plurality of sampling points, filtering part of the samples collected and delivering both unfiltered and filtered samples to various analyzing sensors for making a determination of the quality of the aqueous supply from which the sample is taken through various electrical, chemical and biological means.
2. Description of the Prior Art
With the increased concern for environmental pollution, methods and apparatus for the qualitative and quantitative analysis of aqueous samples are continually being devised. As these improved methods and apparatus are evolved, the time required to perform the tests necessary has been reduced to the point where the apparatus has been taken out of the laboratory category and is now an on-line process system. However, advances in methods of obtaining samples for analysis, and in particular from a water treatment process plan, have not kept pace with the advances in analysis equipment. Additionally, improvements in the analysis equipment hs levied new requirements for filtration of the samples obtained. Again, performance of prior art filter systems have not kept pace with the new requirements.
In the prior art, systems for collecting fluid samples have for the most part been directed to apparatus which is periodically energized to draw the fluid through a sample chamber and into a collection container. With the older, laboratory-type method of testing, which did not require a high volume of waste water effluent to be collected in a short time interval, these methods were adequate. For example, see Peterson, U.S. Pat. No. 3,986,401, which shows a composite sampling method and system for collecting fluid samples from a high velocity effluent. As above-mentioned, the system comprises a pump which is periodically energized to draw fluids through a sample chamber and into a collection container, which may be connected into a testing apparatus or, more conventionally, with the container being periodically transported to a laboratory for subsequent testing of the contained sample.
Prior art filter systems, particularly those associated with silt laden or wastewater discharge, frequently clog with filtrate, requiring cleaning to unclog the filters. In the past, such cleaning has been provided through a backwash or through a flushing process, sometimes known as a "blow-down", involving a rapid rush of unfiltered liquid over but not through the filter mesh element, forcing the clogging material off the filter to a discharge opening for removal. Both of the above-described methods are particularly adaptable for use with the above-described collection system whereby samples are obtained from a process stream only periodically. However, for a sample collection apparatus designed to provide a continuous flow of filtered and unfiltered sample to be used with modern, quick assay apparatus, it becomes cumbersome and inefficient to periodically interrupt the flow of sample collected in order to clear a clogged filter.
The present invention overcomes the deficiencies in the prior art by providing methods and apparatus for automatically and rapidly providing a continuous flow of sample collected from a plurality of distinct "user" selectable sample points and for providing a plurality of continuous output flows in various stages of filtration whereby interruption of one flow to clear a clogged filter may be programmed around the testing procedure.